Quote Originally Posted by zygoteer
Sounds very similar to a Ford I had some years ago - turned out to be the handbrake shoes were simply adjusted too close to the drums and the mechanism allowed the shoes to 'grab' the drum when in reverse, in the manner of a real 'sprag-clutch' ... so maybe check handbrake ?

... but then again that was Ford engineering ... hmmm
Interesting thought. This car has rear disc brakes and not drum brakes. Could this still be an issue?